The goal of this cooperative multicenter study is to reduce the burden of asthma morbidity among underserved, primarily minority, inner-city children ages 4-12. Broad-based, cost-effective asthma interventions will be designed and evaluated. This application from the Tucson consortium consists of community-based HMOs and investigators from the University of Arizona Health Sciences Center (UAHSC). Unique aspects of this application include a Southwest Mexican-American population and investigators with considerable experience in asthma research and management, monitoring of indoor bioaerosols, and asthma outcome measures. Eligible pediatric patients with moderate to severe asthma will be identified using computerized medical records databases of visits during the previous 24 months to outpatient clinics, urgent care clinics, emergency rooms, and hospitals. Only children from families living in previously identified urban census tracts with a high level of poverty and primarily Hispanic will be eligible for the study. Recruitment into the study will be initiated by phone calls to the child's parents and primary care physician, followed by an interview during a scheduled home visit by a Case Manager. A baseline medical and environmental evaluation will be followed by a standard "core" intervention (medical therapy, self-care education, and case management) for the remainder of the study. Three months after recruitment, a randomly selected 50 percent sample of the 200 participants will them be chosen for an extensive 24-month environmental intervention. Asthma outcome measures will then be measured and compared between the two groups at 12 and 24 months.